The present invention relates generally to flexible line trimmer apparatus and, in a preferred embodiment thereof, more particularly provides a simplified, low cost and light weight line trimmer cutting head assembly for containing a supply of flexible cutting line and feeding the line out, in controlled increments, when a depending release button portion of the head assembly is tapped against the ground by the trimmer operator.
"Bump-feed" type cutting head assemblies are now commonly used components of flexible line trimmers and typically comprise a rotationally driven housing in which a spool member is disposed for holding a coiled quantity of flexible cutting line. An outer end portion of the line is extended outwardly through a line exit aperture formed in the housing side wall. During high speed rotation of the housing the outwardly projecting line portion is whirled through a transverse cutting plane to perform its usual vegetation trimming function.
Projecting downwardly from the housing is a release button. When tapped against the ground by the trimmer operator, the release button activates a line escapement structure within the housing to cause relative rotation between the spool and the housing in a manner paying out a predetermined increment of cutting line to re-lengthen the outer line end portion after it has been worn away during vegetation cutting use of the trimmer.
Many conventional bump-feed cutting head assemblies of this general type are characterized by a relatively high degree of mechanical complexity, and a correspondingly large number of separate parts which are necessary to cooperatively form, for example, the incremental line escapement structure, the associated ground bumping mechanism, the housing structure, the spool and its support means, and the connecting structure for operatively securing the trimmer shaft and its internal drive system to the cutting head housing.
This mechanical complexity carries with it several well known, and heretofore unavoidable, problems, limitations and disadvantages. For example, the relatively high number of parts required increases both the material cost and the overall weight (and thus the inertial mass) of the cutting head, and specially designed cutting head assembly tools are often required.
The purchaser/user of the overall trimmer product must also deal with the mechanical complexity incorporated in its conventionally constructed cutting head assembly when it is time to rewind line on its spool, or replace the original spool with one upon which cutting line has been factory prewound. This task typically requires that a lower housing cover portion, and one or more additional cutting head parts, be removed to gain access to the line spool for removal thereof.
What often occurs, either before, during or after spool removal, is that various parts within the housing simply fall out and must be laboriously repositioned in proper sequence and orientation within the housing as a necessary adjunct to spool replacement. This can be a rather tedious and annoying chore for the trimmer user with low levels of patience and mechanical aptitude. Even with patience and mechanical aptitude, a fairly ' high degree of manual dexterity on the part of the user is also often required to reassemble a conventional bump-feed type cutting head assembly since various of its internal parts must be held in alignment while the housing cover is reattached to the main housing body against the force of the release button biasing spring.
In view of the foregoing, it is an object of the present invention to provide a bump-feed type line trimmer cutting head assembly which eliminates or minimizes the above-mentioned and other problems commonly associated with cutting heads of conventional construction.